Variations in Water Quality Characteristics of Serlui River As Impacted by Serlui-B Hydel Project in Kolasib District, Mizoram
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International Journal of Scientific Research in _______________________________ Research Paper . Multidisciplinary Studies E-ISSN: 2454-9312 Vol.3, Issue.6, pp. pp.39-47, June (2017) P-ISSN: 2454-6143 Variations in water quality characteristics of Serlui river as impacted by Serlui-B hydel project in Kolasib district, Mizoram Sangeeta Sunar Department of Environmental Science, Mizoram University, Aizawl, Mizoram, India Corresponding author: [email protected], Mob. +91-9856286089 Available online at: www.isroset.org Received 10th May 2017, Revised 24th May 2017, Accepted 17th Jun 2017, Online 30th Jun 2017 Abstract- The Serlui river is one of the most important natural resource systems in Kolasib district, Mizoram, India. The present study was conducted for a period of one year i.e., from March 2015 to February 2016 to assess the impact of Serlui-B Hydel Project on the water quality of Serlui river, as river water is directly used for drinking and various other domestic purposes by the local people settled in vicinity. Altogether, three sampling sites were selected for detailed investigation along the river from upstream to downstream along the hydel project. The water samples were collected at monthly interval for analysis of various parameters namely, Temperature (22.2˚C-34.3˚C), pH (6.1-7.7), Electrical Conductivity (81µS-154µS), -1 -1 -1 Dissolved Oxygen (5.7-8.1mgL ), Biological Oxygen Demand (0.6-2.2mgL ), Acidity (31-68 mgL CaCO3), Total Alkalinity -1 -1 -1 -1 (18-70mgL CaCO3), Chloride (21-145.67mgL CaCO3), Phosphate-P (0.017-0.210mgL ) and Nitrate-N (0.14-0.60mgL ). The findings reveal that intensity of pollutants increased from Site 1 (Upstream- Control Site) to Site 3 (Downstream), indicating impact of hydel project on river water quality. It is revealed that values are within the prescribed limits as given by various scientific agencies, except Phosphate-P. But long term use of such water may lead to adverse effects on human beings as well as aquatic life. Thus, there is an ample scope of proper treatment of water before use. Keywords: Pollutants, Serlui-B hydel project, Serlui river, Water quality standards, Water treatment. I. INTRODUCTION The developmental activities of hydel project lead to deteriorate river water quality as well as loss of vegetation Water is one of the most essential natural resource of the and degradation of land in catchment area. Keeping this fact, ecosystem that has many uses inclusive of domestic, the present study has been undertaken to critically assess the industrial, commercial, transportation, recreation and impact of hydel project on water quality of the Serlui river. hydroelectric power projects [1]. A great challenge is faced by the world to supply the energy needs of a growing II. MATERIALS AND METHODS population. Hydropower is one of the ideal options for meeting this challenge but the improper management of water Description of study area and study sites systems may cause serious problems in availability and The Serlui river flows through Kolasib district of Mizoram quality of water [2]. Despite the fact that, the northeastern and is impounded by the Serlui-B Dam, 12 km from region has been identified as the future power house of India Bilkhawthlir Village in the Kolasib district. The Serlui-B has as it harbors colossal water assets, the ongoing efforts to a 293m (961 feet) long, 51m (167 feet) high earthfill harness this cosmic hydropower potential through a series of embankment dam, a 135m pressure tunnel and a semi-ground dams has posed an unparalled threat to the water, social and power house [6]. The hydel project has 3 units each with a ecological security of the region. Constructions of dam capacity to generate 4MW power. The dam creates a transform landscapes creating a risk of irreversible impact on reservoir catchment area of 53 square kilometers with life the environment. Hydropower dams involves the setting up of storage capacity of 453.59 cubic million. The catchment area large infrastructure, which in turns obstruct river flow, is 397 square kilometers with an annual rainfall of 3028.6mm transforming the physical and biological characteristics of [6]. river channels and floodplains, fragmenting the continuity of rivers [3], environmental degradation, biodiversity reduction Altogether three sampling sites along the hydel project were [4], leads to deterioration of water quality resulting into selected to study the water quality of Serlui river. nuisance in aquatic environment [5]. 1. Site 1- This site is situated at the upstream of the dam with least anthropogenic activities and © 2017, IJSRMS All Rights Reserved 39 Int. J. Sci. Res. in Multidisciplinary Studies Vol. 3(6), PP (39-47) Jun 2017 maintains its natural flow, and is demarcated as temperature, pH, Electrical Conductivity (EC), Dissolved reference (control site). Oxygen (DO), Biological Oxygen Demand (BOD), Acidity, 2. Site 2- This is diversion inlet of the river where the Total Alkalinity, Chloride, Phosphate-P and Nitrate-N flow of the water recedes with the development of following the methods as outlined in the `Standard Methods the reservoir. for Examination of Water and Wastewater` as prescribed by 3. Site 3- This is diversion outlet situated downstream APHA [7] and compared with standards given by as USPH of river, where the treated river water, after power [8], BIS [9], WHO [10]and ICMR [11]. generation is discharged back into the river. The analysis for the temperature, pH and EC were determined Analytical methods at the place of collection and for analysis of Dissolved Water samples were collected from selected sites on monthly Oxygen content, the water samples were fixed immediately interval (in triplicates) for one year (March 2015- February after collection. The samples were stored in 4˚C for further 2016). Wide mouth bottles were used to collect the samples analysis. The statistical analyses namely correlation with necessary precautions. The water samples were analyzed coefficient, standard deviation and standard error were for various physico-chemical characteristics namely; computed to check the validity and significance of data. III. RESULTS The findings on various water quality attributes are presented herewith in Figure 1-10. A. Temperature: The average temperature was found to be lowest (22.2˚C ±0.67) at Site 1 in the month of January whereas highest value was observed (34.3 ˚C±0.61) at Site 2 in the month of August (Fig: 1). 40 Fig 1: Monthly variaton in water temperature at selected study sites (March 2015- February 2016) 30 20 Site 1 Site 2 Temperature (˚C) 10 Site 3 0 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months B. pH: The present investigation depicts that the pH was lowest (6.1±0.033) at Site 3 in the month of August and highest (7.7±0.088) at Site 2 in February (Fig: 2). Fig 2: Monthly variation in water pH at selected study sites (March 2015- February 2016) 10 8 6 Site 1 pH 4 2 Site 2 0 Site 3 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months © 2017, IJSRMS All Rights Reserved 40 Int. J. Sci. Res. in Multidisciplinary Studies Vol. 3(6), PP (39-47) Jun 2017 C. Electrical Conductivity (EC): In the present study, the lowest value of EC (81µS±1.155) was recorded at Site 1 in the month of February and the highest value (154µS±2.728) was observed at Site 3 in the month of July (Fig: 3). Fig 3: Monthly variation in water EC at selected study sites (March 2015- February 2016) 200 ) 150 100 Site 1 EC EC (µS 50 Site 2 Site 3 0 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months D. Dissolved Oxygen (DO): The DO content was lowest (5.7mgL-1±0.265) at Site 3 in the month of July and highest (8.1mgL- 1±0.115) at Site 2 in the month of December (Fig: 4). Fig 4: Monthly variation in water DO content at selected study sites (March 2015- February 2016) 10 8 ) 1 - 6 Site 1 4 DO DO (mgL Site 2 2 Site 3 0 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months E. Biological Oxygen Demand: The BOD was lowest (0.6mgL-1±0.145) in the month of January at Site 1, on the other hand, highest value (2.2mgL-1±0.115) was seen in Site 3 at the month of July (Fig: 5). Fig 5: Monthly variation in water BOD content at selected study sites (march 2015- February 2016) 2.5 ) 1 - 2 1.5 Site 1 1 0.5 Site 2 BOD (mgL 0 Site 3 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months © 2017, IJSRMS All Rights Reserved 41 Int. J. Sci. Res. in Multidisciplinary Studies Vol. 3(6), PP (39-47) Jun 2017 -1 F. Acidity: The present study revealed that lowest value (31mgL CaCO3±0.155) was recorded at Site 1 in the month of March -1 and highest value (68mgL CaCO3±1.453) was recorded at Site 3 in the month of August (Fig: 6). Fig 6: Monthly variation in water Acidity at selected study sites (March 2015- February 2016) 80 ) 1 - 60 40 Site 1 20 Site 2 Acidity Acidity (mgL Site 3 0 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months -1 G. Total Alkalinity: The present study revealed that lowest value (18mgL CaCO3±1.764) was recorded in the month of -1 March at Site 1 and highest value (70mgL CaCO3±1.155) was observed in the month of September at Site 2 (Fig: 7). Fig 7: Monthly variation in water total Alkalinity at selected study sites (March 2015- February 2016) 80 ) 1 - 60 40 Site 1 20 Site 2 Alkalinity (mgL Alkalinity 0 Site 3 Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Months -1 H.